Electronic structure and thermoelectric properties ofCuRh1−xMgxO2

Abstract

Electronic structure calculations using the augmented spherical wave method have been performed for ${\text{CuRhO}}_{2}$. For this semiconductor crystallizing in the delafossite structure, it is found that the valence-band maximum is mainly due to the $4d$ ${t}_{2g}$ orbitals of ${\text{Rh}}^{3+}$. The structural characterizations of ${\text{CuRh}}_{1\ensuremath{-}x}{\text{Mg}}_{x}{\text{O}}_{2}$ show a broad range of ${\text{Mg}}^{2+}$ substitution for ${\text{Rh}}^{3+}$ in this series, up to about 12%. Measurements of the resistivity and thermopower of the doped systems show a Fermi-liquidlike behavior for temperatures up to about 1000 K, resulting in a large weakly temperature-dependent power factor. The thermopower is discussed both within the Boltzmann equation approach as based on the electronic structure calculations and the temperature-independent correlation functions ratio approximation as based on the Kubo formalism.